Re: General practices???

The White Pass & Yukon used to operate its crews all the way through from Skagway to Whitehorse, 110 miles, and then have the crew hold over for the night and then return the next train.
Sometime after the White Pass dieselized, that routine changed. The unions negotiated an odd deal.
The teamsters, I think, handled the Bennett to Whitehorse run and used a smaller crew. This part of the line is relatively flat and straight.
The crews out of Skagway hauled the train "up the hill" to Bennett Station and swapped trains with the Whitehorse to Bennett train. They did not swap motive power unless a locomotive needed to head to the Shops for work.
Hope this helps.